In current lighting and display field, an organic light emitting diode (OLED) (also known as organic optoelectronic display), featuring a low starting voltage, thinness, lightweight, self-luminous, etc., has by virtue of these received increasing and extensive study for development of the lighting products and the panel industry to meet the demands for low energy consumption, thinness, lightweight, and surface light source.
To reduce the production cost, it is usually required that the raw materials not contain rare or precious metals. As such, the full-organic-material based OLED technology has been favored in recent years. TADF (thermally activated delayed fluorescence)-based OLED has achieved the external quantum efficiency compared to phosphorescent organic light-emitting diodes. Manufacture of such type of devices, however, often requires relatively complex multi-layer device structures and doping processes, which is not conducive to the reduction of manufacturing costs.